Is multicomponent T2 a good measure of myelin content in peripheral nerve?

Abstract

Multicomponent T₂ relaxation of normal and injured rat sciatic nerve was measured. The T₂ relaxation was multiexponential, indicating the multicompartmental nature of T₂ decay in nerve tissue. The size of the short, observed T₂ component correlated very well with quantitative assessment of myelin using computer-assisted histopathological image analysis of myelin. Specifically, the size of the short T₂ component reflected the processes of myelin loss and remyelination accompanying Wallerian degeneration and regeneration following trauma. However, it represented all myelin present in the sample and did not distinguish between intact myelin and myelin debris. Other changes in T₂ spectra were also observed and could be correlated with axonal loss and inflammation. The study also questions the validity of previously offered interpretations of T₂ spectra of nerve. Magn Reson Med 49:638–645, 2003.